#1
In physics at school they are just starting learning about circuits. Being very bored with the material I've decided to add some extras to the project we're doing.

We need to wire a model house with lights, but I'd like to put two or three glowing preamp tubes on the roof. Is there a basic circuit I can use to achieve this? I do not need it to perform any other function, but maybe I'll learn something before I try building an amp by myself.

Can I just connect a power supply to a tube, or will that cause damage without anything else in the circuit?
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#2
I'm no tube expert, but I think you would just have to power the heaters on the tubes.
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#3
^-+1. You just have to wire the tubes heaters (pins 4,5,9 on a 12AX7) for a 12v power supply. But I dont think they are going to glow as much as you may be thinking.
#4
Thanks for the quick replies,

I don't really know how much glow I am expecting, just wanted to do something a little unusual for the project. I'm paired with mexican_shred so we'll probably post a few pictures after it's done. We're hoping to make it into a real "house amp". If we can put his pocket amp back together.
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PM tombo32 to join < 110% credit to t2russo

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Traynor YCV50 Blue
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Boss DD-20
MXR ZW-44
Boss TU-2
#5
Sounds cool
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#6
Just use LED's they will be way easier to put into the circuit and dont require any heaters. just biasing voltage.
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#7
LEDs don't bias...?

I think wiring tube heaters are actually just as easy though. 12v to pin 4 and 0v to pin 5 (or other way around, don't matter).
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#8
When the voltage is positive, current flows easily through the diode. This situation is known as forward biasing
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#9
^I was under the impression that power only flowed one way through diodes? Why call it forward biasing instead of just powering the diode then?
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#10
you are correct diodes allow current to flow one direction. im just used to refering to things as forward or reversed biased. or flow, no flow. you can generally speak of "powering" a diode. but when you look at it component level you have to forward bias it, by putting the proper voltage + or - on the correct side Anode/cathode.

basically im just used to refering to things at component level cause of my job.
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#11
You're right. Now that I think of it that term is vaguely familiar. I'm used to it in the tube/transistor sense.


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I'm a retired Supermod off to the greener pastures of the real world.
#12
No worries! i had to make sure i was right too! made me second guess myself :P
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#13
Out of interest, what field do you work in?
"Everybody, one day will die and be forgotten. Act and behave in a way that will make life interesting and fun. Find a passion, form relationships, don't be afraid to get out there and fuck what everyone else thinks."
#14
im in the air force. i am Airfield systems technician. basically i maintain landing systems for the planes, communications for the tower, base, varying from hf,vhf,uhf,microwave, IR, equipment. its pretty fun, i get to mess with electronics all the time.
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#15
Sounds pretty good, I've got two friends who just signed up to be systems technician in the Army.
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#16
ARMY :P

JP anything electronics is good by me. its a great and rewarding career field.
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#17
I just enrolled for an Advanced Diploma in Electrical Engineering, we don't do tubes though
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